Studying seashells of sea snails may seem ridiculous to some, especially when the research is being paid for by the Department of Defense. But studies of the abalone have paid major dividends in developing the next generation of protective armor and fighter planes for U.S. troops.
Abalone are a delicacy in California. But scientists are more interested in their shells, which are lined with mother-of-pearl, referred to by scientists as nacre.
Researchers have long wondered why nacre is so strong: 3,000 times more break-resistant than the relatively weak calcium carbonate material of which it is primarily composed. Although nacre is primarily made up of calcium carbonate, it also contains a small amount of protein. This protein forms the mortar within a brick wall of mineral crystals. Researchers, supported by the Pentagon and using high-powered scientific tools such as the Department of Energy’s (DOE) Advanced Light Source, have discovered that nacre’s unique interlocking layers help account for the shell’s strength, flexibility and break resistance. Engineers have mimicked this special configuration to construct new, high-impact synthetic nacre materials useful for many important defense and other applications.
This research is an example of an exciting new discipline known as biomimetrics, a field that uses nature as a source of inspiration for engineering and technology. The Department of Defense, in particular, is seeking to develop synthetic versions of nacre for future use. Because synthetic nacre is incredibly versatile in its lightness and strength, researchers are looking into designing next-generation armor and fighter planes that offer more robust shielding to protect against bullets, metal shrapnel, or even violent weather.
The Greenleaf Corporation of Pennsylvania distributes a substance that resembles the tight-knit abalone seashell layers. It is incorporated into armor plating used in C-30 and C-141 military aircraft. This super strong, yet lightweight, material offers endurance under stress and resistance to fracturing.
Abalone research has also spawned countless innovations in the medical field. For instance, dentists are using implants with natural nacre coatings for strength and durability. A team from DOE’s Lawrence Berkeley National Laboratory is working to construct artificial bones from nacre-like building blocks that would be less likely to deteriorate over time from the weight of the surrounding tissue.
Inspired by the way that the nacre structure self-assembles, MIT Professor Angela Belcher produced the first rechargeable nano-battery. This micro-sized battery packs plenty of power but requires much less time to recharge. Its self-renewing properties can function as a power supply to many appliances and electronic devices, such as cell phones and iPods.
Whether to provide protection for soldiers or better medical devices for patients, the abalone shell continues to inspire: Its unique structural properties provide a scientific roadmap for new super-strong materials that will have multiple applications in the defense, medical, and commercial sectors.
Story courtesy of the Association of American Universities via the “
Scientific Enquirer” (Volume II, March 2011)